Subject: [alternative-merged] slab-fix-wrong-retval-on-kmem_cache_create_memcg-error-path.patch removed from -mm tree
To: davej@xxxxxxxxxx,cl@xxxxxxxxx,penberg@xxxxxxxxxx,vdavydov@xxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 27 Jan 2014 15:01:45 -0800
The patch titled
Subject: slab: fix wrong retval on kmem_cache_create_memcg error path
has been removed from the -mm tree. Its filename was
slab-fix-wrong-retval-on-kmem_cache_create_memcg-error-path.patch
This patch was dropped because an alternative patch was merged
------------------------------------------------------
From: Dave Jones <davej@xxxxxxxxxx>
Subject: slab: fix wrong retval on kmem_cache_create_memcg error path
On kmem_cache_create_memcg() error path we set 'err', but leave 's' (the
new cache ptr) undefined. The latter can be NULL if we could not allocate
the cache, or pointing to a freed area if we failed somewhere later while
trying to initialize it. Initially we checked 'err' immediately before
exiting the function and returned NULL if it was set ignoring the value of
's':
out_unlock:
...
if (err) {
...
return NULL;
}
return s;
Recently this check was, in fact, broken by commit f717eb3abb5e ("slab: do
not panic if we fail to create memcg cache"), which turned it to:
out_unlock:
...
if (err && !memcg) {
...
return NULL;
}
return s;
As a result, if we are failing creating a cache for a memcg, we will skip
the check and return 's' that can contain crap. Let's fix it by assuring
that on error path there are always two conditions satisfied at the same
time, err != 0 and s == NULL, by explicitly zeroing 's' after freeing it
on error path.
Signed-off-by: Dave Jones <davej@xxxxxxxxxx>
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab_common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/slab_common.c~slab-fix-wrong-retval-on-kmem_cache_create_memcg-error-path mm/slab_common.c
--- a/mm/slab_common.c~slab-fix-wrong-retval-on-kmem_cache_create_memcg-error-path
+++ a/mm/slab_common.c
@@ -249,7 +249,6 @@ out_unlock:
name, err);
dump_stack();
}
- return NULL;
}
return s;
@@ -257,6 +256,7 @@ out_free_cache:
memcg_free_cache_params(s);
kfree(s->name);
kmem_cache_free(kmem_cache, s);
+ s = NULL;
goto out_unlock;
}
_
Patches currently in -mm which might be from davej@xxxxxxxxxx are
origin.patch
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